Abstract:Aiming at the instability of the collapsing gully wall under the influence of dry-wet cycling, we studied the change rule of the tensile strength of the collapsing soil under the different dry and wet cycles in Tongcheng area of Hubei Province through the indoor uniaxial tensile test. The results showed that the tensile strength of the collapsing soil gradually decreased with the increasing of the number of dry-wet cycles, and finally tended to be stable, and the attenuation of tensile strength of different layers of soil mainly concentrated on the first three dry-wet cycles.The attenuation ratio of tensile strength of topsoil, laterite, transition layer and sandy soil layer reached 90%, 82%, 83% and 90%, respectively, and the tensile strength of different layers of soil followed the order of transition layer > laterite layer > topsoil layer > sandy layer. By considering the influence of the depth of different layers and the number of dry-wet cycles, the prediction model of tensile strength attenuation was established, and the prediction value of tensile strength model had a high correlation with the measured value (R2=0.97). The model had guiding significance for the study of the attenuation mechanism of tensile strength of different layers of soil.